The present invention relates to a method for changing the flowering characteristics of plants, preventing the release of pollens due to flowering and keeping varieties from hybridizing.
Gramineous plants are monoclinous and go to seed by self-pollination. Generally, gramineous plants are characterized in that, at the time of flowering, the anthers protrude from the flower and release pollens in the air. For this reason, it is known that the pollens may cover affinous plant varieties reseeding in the neighborhood, and may hybridize with them depending on the varieties.
It is known that there are some specific mutants which neither come into flower nor release pollens among gramineous plants, and that even flowering varieties sometimes pollinate without coming into flower depending on the environment. However, a method of controlling the flowering of flowering varieties is still unknown.
On the other hand, plants having a herbicide-resistant gene are being produced through gene recombination techniques. Herbicide-resistant plants are generated so that they have resistance to herbicide, when other plants are controlled by the herbicide. However, it is pointed out that, since the herbicide-resistant plants hybridize with wild varieties reseeding in the neighborhood through the release of pollens at the time of flowering, wild varieties also obtain resistance and accordingly it becomes difficult to control them with the herbicide. For this reason also, the establishment of a technique for preventing the release of pollens is required.
The object of the present invention is to develop a technique for preventing the release of pollens in order to keep varieties from hybridizing.
As a result of the present inventors"" thorough work directed to achieve the above object, it has become clear that the application of jasmonic acid derivatives to the ears of gramineous plant before the time of flowering inhibits the bloom and prevents the release of pollens.
The present invention relates to:
(1) a method for preventing the release of pollens, which comprises treating gramineous plants with jasmonic acid derivatives,
(2) an agent for preventing the release of gramineous plant pollens, which comprises jasmonic acid derivatives.
The jasmonic herein include all compounds which are considered to have the activity of jasmonic acid, regardless of whether they are natural or synthetic. That is, examples of jasmonic acids do not only include the natural type of (xe2x88x92)-jasmonic acid and (xe2x88x92)-methyl jasmonate, but also racemic mixtures thereof, i.e., (xc2x1)-jasmonic acid and (xc2x1)-methyl jasmonate, and related compounds such as tuberonic acid, epijasmonic acid, cucurbic acid and so on.
The gramineous plants used herein include bristle grass (Setaria viridis), zoysia, Sorghum halepense and foxtail (Alopecurus myosuroides) as well as rice, winter cereals such as barley or wheat, foxtail millet, Japanese millet and so on.
As a method of treatment, it is preferable to spray the agent on the ears in aqueous solution form before the time of flowering. Accordingly, it is also possible to dissolve a tablet containing jasmonic acid derivatives in water and use it as aqueous solution.